1. Technical Field
The present invention relates to a system for providing directory assistance services to telephone users in a telephone network and, in particular, maintaining a connection to a directory assistance platform and providing for automatic reconnection to a directory assistance provider.
2. Discussion of the Related Art
Telephone calls from one party to another are made through telephone networks, with telephone switches and private branch exchanges (“PBX”) employed as necessary in order to connect networks and customers. Customers frequently make use of directory assistance systems to reach their desired parties. When using a directory assistance system (sometimes referred to as a “directory assistance platform”), a caller first dials the appropriate telephone number or access code. Telephone users usually access a directory assistance system through a carrier switching center. Once connected to a directory assistance provider, such as a live operator or a voice server, the caller identifies the party whose telephone number is desired. The correct number is located and may be reported to (by voice or computer-generated speech), and/or dialed for, the caller. It is increasingly common for directory assistance systems to connect the caller to the caller's desired number in addition to, or in place of, simply providing the number to the caller. This is particularly helpful to callers using cellular or other forms of wireless telephones, who may be engaged in other activities at the same time and therefore unable to take note of the number as it is recited. Typically, once the caller has been given the number and/or the number is dialed for the caller, the caller's connection through the directory assistance platform is terminated.
Termination of the connection through the directory assistance platform has a number of disadvantages. For example, if the caller is given or connected to an incorrect telephone number, the caller must contact the directory assistance system again or inquire elsewhere to obtain the correct number. This naturally requires additional action and expense on the caller's part. Moreover, reconnection to the directory assistance platform requires reallocation of directory assistance resources to the customer call. In view of the previous connection through the directory assistance platform, reconnection and reallocation is unnecessary, time consuming, and under some circumstances, wasteful. Similarly, even if the telephone number to which the caller is connected is correct, the line may be busy, there may be no answer, the destination party's telephone network may be inoperable, etc. In such circumstances, the caller often will want to contact a different party, again requiring the aid of the directory assistance system. Requiring separate and repeated connections to a directory assistance platform incurs added monetary expense on the caller's part, because directory assistance platforms typically charge a fee for each separate connection. Conversely, if a caller's connection is maintained to the directory assistance platform, multiple actions may be taken to assist the caller without necessarily incurring such additional fees.
It is known in the art to provide proactive call services to calling and/or called parties. As demonstrated in U.S. Pat. No. 5,414,754, proactive call services allow parties to, for example, establish a conference call to a third party, leave recorded messages for an unavailable called party, or instruct a telephone service provider to repeatedly attempt to connect to an unavailable party for a pre-determined period of time after an unsuccessful call attempt. Most proactive call services are provided only when a call has been successfully established between two (or more) parties. For such call services, one of the parties requests the service by entering a specified access code. Other proactive call services are available only when a call is unsuccessful (e.g., the caller encounters a busy signal or a ring-no-answer condition); to access these services, the caller is prompted to select one from a menu. Both methods suffer the disadvantage of requiring affirmative action by one or more parties in order to access the services.
Prior art directory assistance systems suffer from a further disadvantage in that they typically lack dedicated resources for monitoring telephone connections to calling or called parties. For example, in U.S. Patent No. 5,414,754, one tone detecting device monitors up to 1,344 connections by using a multiplexer. The period of time for which each connection is monitored is critical to this method of operation. To service so many connections on an equal time-sharing basis, the device cannot monitor one particular connection for more than a very short period of time (illustratively, on the order of milliseconds) before switching to and monitoring others. If the time period is too short, this method has the deleterious effect of requiring a party to press a key for an extended period of time—long enough to ensure that the monitoring digital signal processor (“DSP”), perhaps a dual-tone multi-frequency (“DTMF”) receiver, cycles back to the party's connection in time to detect the keypress—or risk the possibility that the DSP will miss the party's keypress. Another disadvantage to this method is that normal voice energy, or transient signals such as from interference or crosstalk, may cause a DSP that is monitoring the connection to mistakenly report that a party pressed a key. This disadvantage is even more pronounced in a wireless environment, where the bit error rate or degraded audio quality of the connection often precludes the receipt of a continuous tone.
Another disadvantage in prior directory assistance systems is the inability to restrict the caller's use of the directory assistance system to connect to specified parties. For example, the party paying for a caller's wireless telephone service may wish to restrict the caller from making any long-distance calls, or to limit the caller to calls to other parties within one organization, etc. Without the ability to limit the caller's connections through the directory assistance system, the caller could circumvent the paying party's restrictions by having the directory assistance system complete the call for him or her.
Accordingly, there is a need in the art to provide a method and apparatus by which a caller can, for the duration of a telephone call (i.e., until the calling telephone disconnects from the directory assistance platform), maintain his or her connection to the directory assistance platform and repeatedly receive directory assistance in a variety of forms with minimal or no action on his or her part. There is also a need in the art for means and an apparatus for allocating a monitoring resource, such as a DSP, to a minimal number of telephonic connections. In addition, there is a need for means and an apparatus for verifying a caller's authorization to connect to a requested destination party through a directory assistance platform.